Magalhães et al [22] demonstrate these polymorphisms of HLA class I and II may be genetic risk for severity of the disease in a case-control study of patients with mild or severe psoriasis, and found that alleles HLA-DRB1*07, B*37, Cw*06 and Cw*12 were correlated with severe disease course. Here, HLA-DRB1 is linked to psoriasis.